Apparatus for bore hole drill and logging



Jan. 16, 1962 J. D. BENNETT ETAL 3,016,963

APPARATUS FOR BORE HOLE DRILL AND LOGGING Filed Nov. 4, 1957 1e 72 96 92 97 1o 90 as Q A2 4- FIG. 2. 82 4s- /38 34 Y n2 1- 48 k az 0 I06 I08 \-s2 3 l2 I0-- I00 Ir; "K

/l6 FIG. 3. m Q

x eg I22 22 /-2a n4 E us FIG. 4.

IN VENTORS JOHN D. BENNETT a FRED M. MAYES ATTORNEYS 3,016,963 APPARATUS FOR BORE HOLE DRILL AND LOGGING John D. Bennett and Fred M. Mayes, Richardson, Tex.,

assignors to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Filed Nov. 4, 1957, Ser. No. 694,257 1 Claim. (Cl. 17592) This invention relates to apparatus for bore hole drilling and logging and, more particularly, to the modification of a hammer drill assembly to permit the projection of a logging assembly below the bit thereof.

Conventional methods of well logging, whether of electrical or other types, involve the absence of the drill stem during the logging operation. This has two serious drawbacks in that not only must special time be consumed in running the well log, during which time the drill stem must be out of the hole, but after a period of drilling, due to the fact that the drill stern must be removed, there is inevitably a delay before the new part of the hole may be logged, during which delay there occurs invasion of the formation by drilling liquid. Since the drilling liquid has physical properties of its own, it may, by penetration of porous layers, greatly change their properties so as to interfere with their detection. For example, in the case of electrical logging, the conductivity of the liquid will effect changes in the apparent conductivity of the formations; and in the case of acoustic logging the absorption and velocity of sound will be changed, etc.

Proposals have been made to effect electrical logging by using the drill bit or one or more other parts of the drill stern as logging electrodes. In line with this it has been proposed to supply special drill stem tubing containing one or more conductors which are electrically connected in the assembly of the drill stern and extend to recording apparatus at the surface. The use of such an arrangement has been found to be impractical because of high cost and wear.

Proposals have also been made to support one or more electrodes on wire lines to be dropped below a core bit into the lower portion of a hole from which the bit has been raised. This procedure has also proved impractical inasmuch as special handling has been required at the surface, but particularly because core bits are not generally desired for the major drilling activities but are used only for special purposes.

In the applications of Mayes and Jones, Serial No. 683,027, filed September 19, 1957, and of Bennett, Chaney, Jones and Mayes, Serial No. 685,717, filed September 23, 1957, there are disclosed methods and apparatus for logging below a drilling bit, which methods and apparatus avoid the shortcomings referred to above. In accordance with the disclosure of said applications, the logging methods and apparatus may be used when a drill string is in a bore hol and may be used at any time with a minimum of interruption of drilling. Not only may the logging be accomplished just prior to removal of the drill string for the purpose of changing a bit, but the logging may be carried out to be promptly followed by a continuation of drilling. In brief, a selfcontained energizing and recording apparatus may be dropped through a drill string in go-devil fashion or may be pumped down therethrough when the drill string has been lifted to only a limited extent from the bottom of the hole to provide a region for reception of an electrode or other logging assembly, The apparatus particularly includes an assembly of a type suitable to pass through the mud flow openings of a jet bit. These jet openings are generally at relatively small angles with respect to the drill stem axis and a flexible assembly 3,0l6,963 Patented Jan. 16, 1962 may, accordingly, be projected therethrough to extend beneath the bit. For electrical logging the assembly is an electrode assembly; for acoustic or other logging it may be of suitable type for exposure to the walls of the hole.

The self-contained assembly which is lowered to the vicinity of the bit contains, for electrical logging, not only means for supplying current to the earth, but also means for recording various potentials at the electrodes of the assembly, the recording being desirably effected magnetically, as disclosed in said prior applications.

There has recently come into use a new type of bore hole drill known as a hammer drill, in which blows are imparted by a hammer to a bit. The hammer is hydraulically operated or controlled, and this requires tortuous passages for the fluid, particularly through a control valve, and these passages are such that a logging element cannot be passed therethrough to project below the bit.

It is the general object of the present invention to provide a hammer drill arrangement through which there is provided a straight or substantially straight passage through which the logging element, for example a tubular elongated member carrying electrodes, may be passed so as to project beyond the bit during a logging operation. Provision is made in accordance with the invention, to close off this passage to prevent such free flow of drilling fluid as would interfere with proper operation of the hammer drill The foregoing general object of the invention as well as others particularly relating to details of construction and operation will become apparent from the following description, read in conjunction with the accompanying drawings, in which:

FIGURE 1 is a vertical section showing one form of hammer drill assembly which may be provided in accord ance with the invention;

FIGURE 2 is a fragmentary section showing an alternative valve arrangement which may be used;

FIGURE 3 is a fragmentary section showing another valve arrangement which may be used; and

FIGURE 4 is a fragmentary section showing a valve controlled by the pressure of the drilling fluid.

The logging assembly, per se, forms no part of the present invention and is indicated merely diagrammatically as will more fully appear hereafter. It may be of the form disclosed in detail in the foregoing applications, consisting of a pressure-tight housing in which is located recording apparatus assembled with a wand which is adapted to project beyond the bit. For consistency of description, the apparatus will be referred to in the form of an electrical logging apparatus in which the wand carries electrodes arranged for the introduction of alternating current into the earth and for pick up of alternating and direct potentials. It will be understood, however, that other logging apparatus may be employed in which a pick up or energizing element is of elongated type and of sufficiently small diameter to pass through passages such as are hereafter described. The term wand has been particularly applied in the applications referred to above because it is flexible but has considerable stiffness to enable it to deflect from a straight condition to pass through the non-axial openings of jet bits. As will appear in the present case, if the bit is provided with an axial passage the wand may be quite rigid, though because of the length which it will normally have and its relatively small diameter it will be somewhat flexible. Flexibility, however, is not then a requirement. However, if the bit has only diverging, non-axial, mud passages, the wand may be more flexible as described in said prior applications. For consistency of description and reference to said prior applications the term wand will be used to describe the element which carries electrodes or other energizing or pick up apparatus, whether flexibility is or is not an important characteristic.

Referring first to FIGURE 1, there is shown therein an assembly which, except for rather minor changes, is a conventional hammer drill. A housing member 2 which is arranged to be secured in conventional fashion to the lower end of a hollow drill stem through which mud is pumped as the drilling fluid, encloses and mounts the operating hammer, the circulated mud entering its neck 4 through passage 6 and being delivered by a side passage 7 to a chamber 8 provided with a lower wall 10 through an Opening in which there may slide the stem 12 of the hammer 14. The stem and hammer are provided with a central passage .16. A powerful spring 18 normally urges the hammer downwardly to cause it to engage and strike blows upon the bit 20 which is provided with a central opening 22 and conventionally with diverging mud passages 24. In the present instance the passage 22 is desirably continued in the form of a central passage 26 which also serves during drilling for the flow of mud. However, in the case of bits which do not have a central axial opening, provision may be made to guide a flexible wand through a non-central opening as described in the aforementioned applications. The bit is free to move axially in the housing 2, being restrained from dropping therefrom by engagement of its flange 28 with the inwardly directed flange 30 of the housing. (It may be here noted that no attempt has been made in the drawing to show separate parts of the hammer drill as may be required for assembly; various parts, which are normally separate but secured together by threads, being shown integral for simplicity.)

The upper end of the hammer stem 12 is provided with a flange 32 having a fiat upper surface to cooperate with the flange 36 at the lower end of a control valve 34. This valve has a central passage 38. It is arranged to reciprocate in a bore through a wall member 40 which delimits the lower end of a chamber 42 which must be closed at its upper end during drilling, and in conventional hammer drills is closed by a solid wall. A relatively light spring 44, as compared with spring 18, urges the valve 34 downwardly. At its upper end the valve is provided with radial ports 46, and in its central portion is provided with passages in the form of slots 48 which have a vertical extent greater than the vertical thickness of the wall 40 so that, at times, they alford passageways between the chamber 8 and the chamber 42. To the extent so far described, the hammer drill is essentially conventional and operates in conventional fashion which may be briefly outlined as follows:

As the drill is being lowered in the hole, the bit 20 drops to the lowermost position permitted by the flanges 28 and 30. The hammer 14 under the action of spring 18 rests on the bit, and the valve 34, urged by spring 44, rests on the hammer stem. Under these conditions, the ports 46 are below the wall 40 so that free circulation of mud may take place through the passages 6 and 7 to the chamber 8 and thence through ports 46 into the interior passage 38 of the valve and downwardly through passage 16 and the openings in the bit. When drilling is to be accomplished, the bit is lowered until it is arrested at the bottom of the hole, and further downward movement of the drill stem produces a rise of the hammer 14 relative to the housing 2. Under these conditions, the ports 46 are raised within or above the wall 40 and the mud pressure acting on the area of the flange 32 raises the hammer and the valve 34, compressing the spring 18. As this upward movement continues, the passages 48 provide communication between the cham bers 8 and 42, and the pressure above the valve flange or lip 36 is relieved and the hammer drops away from the valve to strike a blow under the action of spring 18 against the bit. The valve then drops into contact with the flange 32 and the operation is repeated to deliver successive blows to the hammer. As stated, this action is conventional, and it is described merely because it shows that during such operation it is essential that the chamber 42 be closed against direct mud pressure. Accordingly, for proper operation, it cannot have in its upper end a clear passage for the projection of the log ging wand.

In order to provide for proper hammer operation and also for passage of the wand for logging purposes, the upper bounding wall 50 of the chamber 42 is provided with a through opening 52 which is intersected by a bore 54 which slidably mounts a valve 56 having a passage 58 which may be aligned with the passage 52, a spring 60 normally urging the valve 56 toward the right to bring the passages into alignment. A vertically slidable rod 62 is provided with a sloping cam surface 64 at its upper end arranged to engage a corresponding cam surface on the valve. This rod 62 has an extension 68 arranged to be operated upon by the bit 20 to be pushed upwardly when the bit rests on the bottom of the hole. The arrangement is such that when the bit is freely suspended the spring 68 will move to the right to provide the through opening necessary for the wand. During drilling, however, the rod 62 forces the valve toward the left to close off the passage and thereby establish the conditions necessary for hammer operation.

The wall 50 is desirably provided with a conical depression 70 in its upper end communicating with the passage 52 so as to guide the wand 72 into the passage. The wand 72 may be of the type disclosed in said prior applications, and may be provided, as described therein, primarily by a coiled spring, carrying, additionally, electrodes such as 74 and 76 in the case of electrical logging apparatus, the wand being otherwise externally insulated. In the case of the present apparatus, however, the wand may be essentially rigid, if the bit has an axial central passage, except for the possibility of fiexure due to its considerable length which may ordinarily be upwards of twenty feet. The wand is carried by the lower end of the housing 78 within which there is located the current-providing and recording apparatus of the type disclosed in said prior applications, or of some other type if the logging is other than electrical.

The operation of drilling has already been described. When it is desired to effect logging, the bit will be raised a suitable distance above the bottom of the hole and as it drops relative to the housing 2 the spring 60 will move valve 56 to the right to open a clear passage for the wand. The logging apparatus may then be dropped or lowered through the drill stern and the wand will pass through the opening 52 and through the centrally aligned openings 38, 16 and 26 to be projected a suitable distance below the bit into the open portion of the hole. If the bit does not have a central axial opening, a flexible wand may be guided through a non-central opening as described above. The housing 78 may be brought to rest in any suitable fashion, and there may be used a cushioning arrangement such as shown in said prior applications to prevent damage by impact. After the logging apparatus is thus located in position, the drill stem may be raised and logging effected as described in said prior applications, there being noted corresponding times and depths so that the record made within the housing 78 may be ultimately related to depth. Following completion of the logging operation, the logging apparatus may be pulled up by a supporting wire line, if it has been lowered thereby, may be retrieved by an overshot if it has been dropped or pumped down, or may be left within the drill stem if immediately following the logging the drill stem is to be withdrawn for changing of the bit.

It will be apparent from the foregoing that the apparatus which has been described consistently provides for both operation of the hammer and for logging by means of a device which is to be projected through the bit.

FIGURE 2 shws an alternative valve arrangement which may be used. In this case the housing 80 corresponds to housing 2 and it will be understood that the hammer operating arrangement is the same as previously described, the chamber 82 corresponding to chamber 42. In this case the upper wall of this chamber is provided with an opening 34 aligned with which there is the socket 86 arranged to receive a valve 88 which may be made of natural or synthetic rubber and Which is molded to provide a stem portion 92 which is constricted as indicated at 94 to close off the opening therethrough, the portion of the extension 92 above the constriction being flared as indicated at 96. The valve is secured in position by a snap ring 90. Above this there is desirably the converging wand guiding member 98 which will insure a central position of the lower end of the wand to cause it to enter properly the valve 88 and the central opening 84. A diverging diffuser passage 99 in member 98 serves to reduce the linear velocity of the mud flowing therethrough to reduce impact which might tend to open the valve. The valve arrangement is such that it is normally closed at the constriction 94 and is held tightly closed by reason of the differential mud pressure existing between its exterior and interior. Under these conditions the chamber 82 is closed and consequently hammer operation may occur in normal fashion. When logging is to be effected, the wand 72 will enter the opening provided by the flared portion of the valve at 96 and the thrust due to the logging apparatus will cause it to open and pass through the valve and the opening 84, the wand thereafter passing through the aligned passages previously described. To insure normal closure of the valve there may be molded into it a metal ring 95 provided with spring fingers 97 tending to move inwardly. These fingers will flex outwardly to permit the wand to pass. The exterior of the valve may also be shaped so that pressure thereagainst due to mud flow will counteract any tendency for opening provided by impact of mud into the flaring mouth of the valve.

FIGURE 3 shows still another modification in which the housing 100 corresponding to the housing 2 has a chamber 102 corresponding to chamber 42 previously described. In this case the upper end of the chamber is closed by a wall containing the central opening 104 above which, in a circular socket, there is a rubber valve 106 which is normally closed at 108, being retained in position by the snap ring 110. Guiding means 112 is provided as previously described to center the wand. Here, again, differential mud pressure across the valve by compression of the valve normally maintains its opening in closed condition, but the wand may readily penetrate enlarging the opening for its passage.

In the modification shown in FIGURE 4, the housing 114, containing the chamber 116 corresponding to chamber 42 has its upper bounding wall provided with an opening 118 across which there is located the bore 120 which is open at its left-hand end at 122 for exposure to the mud pressure. A slide valve 124 is arranged in this bore, being splined as indicated at 125 so as to be held against rotation. The valve 124 is provided with an opening 126 arranged to align with the opening 118 when the valve is urged toward the left by spring 128 housed in the threaded retainer 130. Under conditions of drilling the mud pressure differential between 122 and the exterior of the drill stem is high and consequently the valve is moved to the right to close the chamber 116. When the pressure is relieved, for logging purposes, the valve is moved toward the left by the spring 128 to provide an opening for the passage of the wand.

It will be evident from the foregoing that other variations of construction may be adopted, all for the purpose of providing a free direct passage for the wand while maintaining proper closure of a chamber corresponding to 42 during drilling.

What is claimed is:

A drill assembly for use with a logging means and arranged for connection to the lower end of a hollow drill stem, comprising a bit, hammer means controlled by fluid flowing through such drill stem for imparting blows to said bit to effect drilling movements thereof, said means including non-aligned fluid passages for its operation preventing direct passage through the hammer means of said logging means adapted to operate by projection beyond said bit, said first mentioned means being provided with an auxiliary passage through which such logging means may pass, and means permanently located in said assembly and closing said auxiliary passage during drilling to restrict downward flow of fluid under pressure through said auxiliary passage but arranged to be opened following a drilling operation but while the bit remains in the hole, for downward passage of said logging means through said auxiliary passage for a logging operation, said closing means comprising a valve of yielding material having a central passageway normally closed by inward position of the yielding material but arranged to open upon insertion of said logging means into the central portion of the valve.

References Cited in the file of this patent UNITED STATES PATENTS 699,273 Wolski May 6, 1902 1,813,368 Toles July 7, 1931 2,070,912 McDermott Feb. 16, 1937 2,254,641 Bannister Sept. 2, 1941 2,661,928 Topanelian Dec. 8, 1953 2,724,442 Mundt Nov. 22, 1955 2,786,535 Boer et al Mar. 26, 1957 2,890,859 Garrison June 16,, 1959 FOREIGN PATENTS 206,296 Germany Feb. 1, 1909 

